The US Air Force has been busy testing its latest robotic space plane, the X-37B. The vehicle is 29 feet (8.8 meters) long and 15 feet (4.5 m) wide, with a payload bay about the size of a pickup truck bed. It was launched into orbit via an Atlas 5 rocket on Dec. 11, 2012, and is still circling the Earth. This is the third such mission for this mini-shuttle, and the Air force is keeping quite secret about its purpose.

Now, as die-hard SF fans, we can form our own speculations about this project, can't we? So let's try:

Equip it with a pressurized module, and it becomes a rescue craft for astronauts on the International Space Station. No more total dependance on the Russians.

Give it enough fuel, and it can land on the Moon, paving the way for a new US presence. Baby-boomers have been waiting for at least three decades on this one.

Is there another secret, manned US Air Force Space Station in orbit being resupplied by the X-37? Hmm, one wonders. Does International Rescue really exist? You can have lots of fun with that one!

The second mission for this vehicle lasted 469 days, proving its reliability as a renewable, long-term spacecraft. But until the Air Force lifts all the secrecy, fans of the space program will have to settle for